1. Technical Field
The present invention relates to an image processing apparatus and a computer readable medium.
2. Related Art
A technique is developed which detects a failure in an image forming apparatus, such as a copy machine, a printer, a scanner, or the like, and estimates the cause of failure.
As an example of defect detection in image data obtained by inputting a sheet with a test pattern printed thereon, it is determined whether or not the background color of the sheet with the test pattern thereon printed is white, and when the background color is not white, the occurrence of defects is detected. In this example, if a test pattern is printed on a colored sheet having a background color other than white or a sheet which originally had a white background color but underwent yellowing due to deterioration or the like, and image data obtained by inputting the test pattern through a scanner is analyzed, since the background color is not white even though no defect actually occurred in image data, it may be determined that a defect has occurred in the image. Such erroneous determination can be prevented by a defect detection processing using image data which is obtained by removing or correcting the background color when the detection of the background color of image data shows the background color to be a chromatic color.
One type of defect in the image printed on the sheet is that toner is stuck so as there is a thin covering over a partial area of the sheet or the entire surface of the sheet. Such a defect in the image is hereinafter called “background staining”. According to the technique in which, when the background color of a chromatic color is detected in image data, after the background color is removed or corrected, image data is analyzed and failure diagnosis of the image forming apparatus is performed. In this way, the background color of a chromatic color due to toner sticking may be removed or corrected, and the occurrence of background staining will not be detected.